Add automatic release process

[ShimShtein]

• Add a RELEASE.md file. Example: https://github.com/theforeman/foreman_plugin_template/blob/master/RELEASE.md
• Add an automatic release action. Example: https://github.com/theforeman/foreman_plugin_template/blob/master/.github/workflows/release.yml

For more context see the original RFC thread: https://community.theforeman.org/t/rfc-the-perfect-release-process/